Torque limiting method and device, vehicle and storage medium

Abstract

The invention provides a torque limiting method and device, a vehicle and a storage medium. When the current charging power allowed by the power battery is low and the vehicle is in the energy recovery working condition, a protection mechanism for the power battery is triggered, and unnecessary energy recovery is avoided. Besides, the required power of the vehicle-mounted electric equipment directly affects the net charging / discharging capacity of the power battery, the current charging power directly reflects the charging capacity upper limit of the power battery, and the target braking torque can complement the residual torque requirement which cannot be met by the driving motor, so that the driving efficiency is improved. Through the demand power, the current charging power and the target braking torque of the vehicle-mounted electric equipment, the recovery torque limit value of the driving motor during energy recovery can be accurately determined. Furthermore, by strictly executing the recovery torque limit value, it can be ensured that the charging power generated by the driving motor during energy recovery is always within the acceptable range of the power battery, and therefore the problem that the power battery is overcharged for a long time due to energy recovery is avoided.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and more specifically, to a method, a device, a vehicle and a storage medium for limiting torque in the field of vehicle technology. Background Art

[0002] With the continuous advancement of vehicle technology and the improvement of people's living standards, the audience of vehicles is becoming more and more extensive. However, there are also more and more vehicle-related problems, including the problem of long-term overcharging of power batteries during driving.

[0003] In some embodiments, when the power battery in a pure electric vehicle is in a low temperature environment, the charging power allowed by the power battery is very low. If the pure electric vehicle is in an energy recovery state, the drive motor in the pure electric vehicle will be converted to a generator mode and generate a feedback current. However, when the charging power allowed by the power battery is very low, the power battery cannot absorb these currents well, which will cause the voltage of the power battery to increase, which may cause the electrolyte in the power battery to decompose and release a large amount of heat, causing fire or explosion, etc.

[0004] Therefore, a method for limiting torque is urgently needed to avoid the problem of long-term overcharging of the power battery in the above scenario as much as possible. Summary of the invention

[0005] The present application provides a method, device, vehicle and storage medium for limiting torque, which can prevent the power battery from being overcharged for a long time when the current charging power allowed by the power battery is very low and the vehicle is in an energy recovery condition.

[0006] In a first aspect, a method for limiting torque is provided, the method comprising: when a vehicle is in a driving state and a current charging power allowed by a power battery in the vehicle is less than or equal to a preset power, detecting whether the current driving condition of the vehicle is an energy recovery condition, the preset power being used to indicate that the power battery is currently not suitable for charging; when the driving condition is an energy recovery condition, determining a recovery torque limit of a drive motor in the vehicle during energy recovery based on the required power of the on-board electrical equipment, the current charging power and a target braking torque, the target braking torque being a braking torque limit independently provided by a mechanical braking system of the vehicle under the energy recovery condition; and controlling the recovery torque of the drive motor during energy recovery to not exceed the recovery torque limit.

[0007] In the above technical solution, when the current charging power allowed by the power battery is relatively low and the vehicle is in the energy recovery working condition, a protection mechanism for the power battery is triggered to limit the input of electric energy at the source and avoid energy recovery when it is not necessary. In addition, the required power of in-vehicle electrical equipment directly affects the net charging / discharging capacity of the battery, and the current charging power can directly reflect the upper limit of the real-time charging capacity of the power battery. And the above target braking torque is the redundant capacity of mechanical braking, and mechanical braking can make up for the remaining torque requirements that the drive motor cannot meet. Therefore, through the required power of in-vehicle electrical equipment, the current charging power, and the target braking torque, the recovery torque limit of the drive motor during energy recovery can be accurately determined. Further, by strictly implementing the recovery torque limit, it can be ensured that the charging power generated by the drive motor when the vehicle is in the energy recovery working condition is always within the acceptable range of the power battery, thus avoiding the problem of overcharging of the power battery for a long time due to energy recovery.

[0008] In combination with the first aspect, in some possible implementation manners, based on the required power of in-vehicle electrical equipment, the current charging power, and the target braking torque, determining the recovery torque limit of the drive motor in the vehicle during energy recovery includes: determining an initial recovery torque limit of the drive motor during energy recovery based on the required power, the current charging power, and the target braking torque; determining a torque correction coefficient based on whether the driving direction of the vehicle is consistent with the gear state, where the torque correction coefficient is used to correct the initial recovery torque limit; and determining the product of the initial recovery torque limit and the torque correction coefficient as the recovery torque limit during the vehicle's driving.

[0009] In the above technical solution, determining the initial recovery torque limit through the required power of in-vehicle electrical equipment, the current charging power, and the target braking torque can ensure that the braking torque limit of the drive motor is always limited by the current acceptable charging power of the power battery. Subsequently, the consistency judgment of the driving direction and the gear state is introduced to generate a torque correction coefficient to dynamically adjust the initial recovery torque limit. This dual control mechanism can not only rigidly constrain the energy recovery power through the current charging power of the power battery in the initial calculation stage, but also further suppress the recovery torque limit through gear abnormality detection in the correction stage of the torque correction coefficient. This can achieve refined management and control of the recovery torque under multi-dimensional dynamic working conditions and prevent the long-term overcharging risk caused by the recovered electric quantity of the power motor exceeding the current charging capacity of the power battery.

[0010] Combined with the first aspect and the above implementation manners, in some possible implementation manners, determining an initial recovery torque limit value of the drive motor during energy recovery based on the required power, the current charging power, and the target braking torque includes: determining a difference between the current charging power and the required power as the current available charging power of the power battery, and determining the larger power of the available charging power and a first preset power as the available recovery power; determining a ratio of the available recovery power to the current speed of the drive motor as a first torque; and determining the smaller torque of the first torque and the target braking torque as the initial recovery torque limit value.

[0011] In the above technical solution, by using the power difference between the current charging power and the required power of in-vehicle electrical equipment as the available charging power, it can be ensured that the upper limit of the energy recovery power is always lower than the net remaining power obtained by subtracting the power consumed by the on-vehicle charging device from the charging power acceptable to the power battery. Further, taking the larger power of the power difference and the first preset power as the final available recovery power, that is, using the first preset power as the power safety threshold, this can prevent the available power from becoming negative or too low due to a sudden increase in the required power. Subsequently, a first torque is determined based on the ratio of the available recovery power to the current speed of the drive motor, and then the smaller value is taken after combining with the target braking torque to determine the initial recovery torque limit value. The above torque limiting mechanism dynamically couples the charging power of the power battery, the equipment load, the speed characteristics, and the mechanical braking torque at the calculation source. By gradually taking the boundary values with more stringent constraints, it can be ensured that the recovery torque of the drive motor will not cause the input power of the power battery to exceed its currently allowed maximum charging power under any working conditions, thereby reducing the risk of long-term overcharging of the power battery.

[0012] Combined with the first aspect and the above implementation manners, in some possible implementation manners, determining a torque correction coefficient based on whether the driving direction of the vehicle is consistent with the gear state includes: when the driving direction is consistent with the gear state, determining a first correction coefficient as the torque correction coefficient, where the first correction coefficient is used to indicate that the initial recovery torque limit value remains unchanged; when the driving direction is not consistent with the gear state, determining a second correction coefficient based on the slip ratio of the drive wheels in the vehicle, the current vehicle speed, and the remaining power of the power battery, and determining the second correction coefficient as the torque correction coefficient, where the second correction coefficient is less than the first correction coefficient.

[0013] In the above technical solution, when the driving direction is consistent with the gear state, the first correction coefficient (usually 1) is used to keep the initial recovery torque limit unchanged, which can ensure the maximization of the energy recovery efficiency under normal working conditions. When the driving direction is inconsistent with the gear state, the slip rate of the driving wheel, the current vehicle speed, and the remaining power of the power battery are introduced to dynamically determine the second correction coefficient (usually less than 1). The slip rate can reflect the state of the wheel grip (when the slip rate is too high, the energy recovery intensity is reduced to avoid wheel slip and exacerbate energy mutation). The current vehicle speed is used to affect the time accumulation effect of the recoverable power, and the remaining power can be directly related to the power threshold of the overcharge risk of the power battery. The above-mentioned multi-parameter coupling correction logic can actively reduce the recovery torque limit under abnormal working conditions (energy recovery working condition and current charging power is low), so as to avoid the power battery from receiving power input exceeding its allowable charging power in a short time. At the same time, combining the slip rate and the remaining power can build a double safety line to systematically block the long-term overcharge risk abnormally caused by mechanical and electrical coupling.

[0014] Combined with the first aspect and the above implementation, in some possible implementations, based on the slip rate of the driving wheel, the current vehicle speed, and the remaining power of the power battery in the vehicle, the second correction coefficient is determined, including: determining a third correction coefficient based on the slip rate, the safety slip rate threshold of the driving wheel, and the maximum allowable slip rate; determining a fourth correction coefficient based on the current vehicle speed, the low speed threshold, and the high speed threshold of the vehicle; determining a fifth correction coefficient based on the remaining power, the low power threshold, and the high power threshold of the power battery; and determining the product of the third correction coefficient, the fourth correction coefficient, and the fifth correction coefficient as the second correction coefficient.

[0015] In the above technical solution, the influence of the slip ratio of the driving wheel, the current vehicle speed of the vehicle, and the remaining power of the power battery on the torque correction coefficient is decoupled hierarchically. Based on the dynamic relationship between the slip ratio and its safety threshold and maximum allowable threshold, the third correction coefficient is determined. According to the mapping of the current vehicle speed within the range between the low-speed threshold and the high-speed threshold, the fourth correction coefficient is determined. According to the mapping of the remaining power within the range between the low-power threshold and the high-power threshold, the fifth correction coefficient is determined. Furthermore, the second correction coefficient is synthesized through the product of the three (the third correction coefficient, the fourth correction coefficient, and the fifth correction coefficient). This multi-dimensional interlocking constraint mechanism can directly weaken the regenerative torque limit when the slip ratio is abnormal to avoid the risk of mechanical energy mutation. The current vehicle speed can suppress the energy density of large inertia regeneration when the vehicle is at high speed. The remaining power serves as a hard attenuation factor for final overcharge protection. After the three are superimposed, a strict product attenuation can be imposed on the initial regenerative torque limit, ensuring that the regenerative torque of the drive motor is always compressed within the safety boundary of the charging power currently allowed by the power battery. This can avoid the risk of long-term overcharging of the power battery when the current charging power allowed by the power battery is low and the vehicle is in the energy regeneration working condition.

[0016] Combined with the first aspect and the above implementation manners, in some possible implementation manners, based on the slip ratio, the safety slip ratio threshold of the driving wheel, and the maximum allowable slip ratio, determining the third correction coefficient includes: in the case where the slip ratio is less than or equal to the safety slip ratio threshold, determining the sixth correction coefficient as the third correction coefficient; in the case where the slip ratio is greater than the safety slip ratio threshold and less than or equal to the maximum allowable slip ratio, determining the slip ratio deviation between the slip ratio and the safety slip ratio threshold, and determining the first coefficient difference between the preset coefficient and the seventh correction coefficient as the third correction coefficient, where the seventh correction coefficient is the product of the slip ratio deviation and the first attenuation coefficient, and the first attenuation coefficient is used to indicate the attenuation amount of the torque correction coefficient corresponding to each unit percentage increase in the slip ratio; in the case where the slip ratio is greater than the maximum allowable slip ratio, determining the eighth correction coefficient as the third correction coefficient, where the sixth correction coefficient is greater than the first coefficient difference, and the first coefficient difference is greater than the eighth correction coefficient.

[0017] In the above technical solution, the influence of the slip ratio on the correction coefficient is processed in intervals. When the slip ratio does not exceed the safety slip ratio threshold, the initial recovery torque limit value is not changed at the angle of the slip ratio, ensuring the optimal energy recovery efficiency under the condition of low slip ratio. When the slip ratio is between the safety slip ratio threshold and the maximum allowable slip ratio, the correction coefficient is dynamically reduced based on the product of the slip ratio deviation and the first attenuation coefficient, so that the initial recovery torque limit value decreases linearly with the degree of slip deterioration, suppressing the sudden input of non-steady-state electric quantity caused by the driving wheel slipping. When the slip ratio exceeds the maximum allowable slip ratio, an extremely low eighth correction coefficient (such as approaching zero) is directly adopted to completely block the possibility of triggering energy recovery at high slip ratios. This stepped attenuation mechanism can gradually tighten the limit on the recovery torque as the slip ratio gradually increases, preventing the instantaneous electric quantity input from exceeding the current acceptable charging power threshold of the power battery. At the same time, when the current charging power allowed by the power battery is low and the vehicle is in the energy recovery working condition, the risk of overcharging the power battery for a long time is eliminated through hard limiting.

[0018] Combined with the first aspect and the above implementation manners, in some possible implementation manners, the method for determining the target braking torque includes: when the mechanical braking system is not braking, determining the sum of the maximum braking torques of the brake calipers of multiple wheels in the vehicle as the target braking torque; when the mechanical braking system is braking, for any wheel in the vehicle, determining the product of the friction coefficient, braking pressure, effective piston area and effective brake disc radius of the brake caliper of the wheel as the braking torque of the brake caliper of the wheel; and determining the sum of the braking torques of the multiple wheels as the target braking torque.

[0019] In the above technical solution, different from the braking state of the mechanical braking system, when the mechanical braking system is not in the braking state, the maximum braking torques of the brake calipers of each wheel are used to determine the target braking torque; while when the mechanical braking system is in the braking state, the target braking torque is determined based on the dynamic product of the friction coefficient, braking pressure, effective piston area and effective brake disc radius. This can more accurately reflect the actual available mechanical braking torque of the vehicle, thereby providing accurate input parameters for the determination of the recovery torque limit value and effectively avoiding overcharging of the power battery caused by estimation deviation of the recovery torque. At the same time, it can also improve the cooperative control accuracy of the braking torque of the driving motor and the braking torque of the mechanical system under the energy recovery working condition.

[0020] Combined with the first aspect and the above implementation manners, in some possible implementation manners, before controlling the recovery torque of the drive motor during energy recovery not to exceed the recovery torque limit value, the method further includes: determining the required braking torque of the driver of the vehicle; and controlling the recovery torque of the drive motor during energy recovery not to exceed the recovery torque limit value, including: when the required braking torque is greater than the recovery torque limit value, controlling the recovery torque of the drive motor during energy recovery not to exceed the recovery torque limit value, and determining the torque deviation between the required braking torque and the recovery torque limit value; controlling the mechanical braking system to brake according to the torque deviation.

[0021] In the above technical solution, through the coordinated action of dynamically distributing the braking of the drive motor and the mechanical braking, when the required braking torque of the driver exceeds the recovery torque limit value, the recovery torque of the drive motor is preferentially and strictly limited within the safety boundary of the power battery, ensuring that the energy recovery power does not exceed the hard constraint of the charging power currently allowed by the power battery. Further, the torque deviation is determined and handed over to the mechanical braking system for compensation. This hierarchical control mechanism can not only directly block the overcharging risk of the power battery at the source, but also make up for the demand of the remaining braking torque in real time through the mechanical braking system, ensuring the matching of the braking performance and the driving intention, and avoiding the insufficient braking of the whole vehicle caused by simply limiting the recovery torque of the drive motor, and then being forced to increase the energy recovery power, triggering the overcharging of the power battery for a long time, etc.

[0022] In a second aspect, a torque limiting device is provided. The device includes: a detection module, configured to detect whether the current driving condition of the vehicle is an energy recovery condition when the vehicle is in a driving state and the current charging power allowed by the power battery in the vehicle is less than or equal to a preset power, where the preset power is used to indicate that the power battery is currently not suitable for charging; a determination module, configured to determine a recovery torque limit value of a drive motor in the vehicle during energy recovery based on the required power of on-vehicle electrical equipment, the current charging power, and a target braking torque when the driving condition is an energy recovery condition, where the target braking torque is a braking torque limit value independently provided by the mechanical braking system of the vehicle under the energy recovery condition; and a control module, configured to control the recovery torque of the drive motor during energy recovery not to exceed the recovery torque limit value.

[0023] Combined with the second aspect, in some possible implementation manners, the determination module is specifically configured to: determine an initial recovery torque limit value of the drive motor during energy recovery based on the required power, the current charging power, and the target braking torque; determine a torque correction coefficient based on whether the driving direction of the vehicle is consistent with the gear state, where the torque correction coefficient is used to correct the initial recovery torque limit value; and determine the product of the initial recovery torque limit value and the torque correction coefficient as the recovery torque limit value when the vehicle is driving.

[0024] Combined with the second aspect and the above implementation manners, in some possible implementation manners, the determining module is specifically further configured to: determine the difference between the current charging power and the required power as the currently available charging power of the power battery, and determine the larger power between the available charging power and the first preset power as the available recovery power; determine the ratio of the available recovery power to the current speed of the drive motor as the first torque; and determine the smaller torque between the first torque and the target braking torque as the initial recovery torque limit value.

[0025] Combined with the second aspect and the above implementation manners, in some possible implementation manners, the determining module is specifically further configured to: when the driving direction is consistent with the gear state, determine the first correction coefficient as the torque correction coefficient, where the first correction coefficient is used to indicate that the initial recovery torque limit value remains unchanged; when the driving direction is not consistent with the gear state, determine a second correction coefficient based on the slip rate of the drive wheels in the vehicle, the current vehicle speed, and the remaining power of the power battery, and determine the second correction coefficient as the torque correction coefficient, where the second correction coefficient is less than the first correction coefficient.

[0026] Combined with the second aspect and the above implementation manners, in some possible implementation manners, the determining module is specifically further configured to: determine a third correction coefficient based on the slip rate, the safety slip rate threshold of the drive wheels, and the maximum allowable slip rate; determine a fourth correction coefficient based on the current vehicle speed, the low speed threshold and the high speed threshold of the vehicle; determine a fifth correction coefficient based on the remaining power, the low power threshold and the high power threshold of the power battery; and determine the product of the third correction coefficient, the fourth correction coefficient and the fifth correction coefficient as the second correction coefficient.

[0027] Combined with the second aspect and the above implementation manners, in some possible implementation manners, the determining module is specifically further configured to: when the slip rate is less than or equal to the safety slip rate threshold, determine the sixth correction coefficient as the third correction coefficient; when the slip rate is greater than the safety slip rate threshold and less than or equal to the maximum allowable slip rate, determine the slip rate deviation between the slip rate and the safety slip rate threshold, and determine the first coefficient difference between the preset coefficient and the seventh correction coefficient as the third correction coefficient, where the seventh correction coefficient is the product of the slip rate deviation and the first attenuation coefficient, and the first attenuation coefficient is used to indicate the attenuation amount of the torque correction coefficient corresponding to each unit percentage increase in the slip rate; when the slip rate is greater than the maximum allowable slip rate, determine the eighth correction coefficient as the third correction coefficient, where the sixth correction coefficient is greater than the first coefficient difference, and the first coefficient difference is greater than the eighth correction coefficient.

[0028] Combined with the second aspect and the above implementation manners, in some possible implementation manners, the determining module is further specifically configured to: when the mechanical braking system is not braking, determine the sum of the maximum braking torques of the brake calipers of multiple wheels in the vehicle as the target braking torque; when the mechanical braking system is braking, for any wheel in the vehicle, determine the product of the friction coefficient, braking pressure, effective piston area and effective brake disc radius of the brake caliper of the wheel as the braking torque of the brake caliper of the wheel; and determine the sum of the braking torques of the multiple wheels as the target braking torque.

[0029] Combined with the second aspect and the above implementation manners, in some possible implementation manners, before controlling the recovery torque of the drive motor during energy recovery not to exceed the recovery torque limit value, the determining module is further configured to determine the required braking torque of the driver of the vehicle; the control module is specifically configured to: when the required braking torque is greater than the recovery torque limit value, control the recovery torque of the drive motor during energy recovery not to exceed the recovery torque limit value, and determine the torque deviation between the required braking torque and the recovery torque limit value; and control the mechanical braking system to brake according to the torque deviation.

[0030] In a third aspect, a vehicle is provided, including a memory and a processor. The memory is used to store executable program code, and the processor is used to call and run the executable program code from the memory, so that the vehicle executes the method in the first aspect or any one of the possible implementation manners of the first aspect. Description of the Drawings

[0031] Figure 1 is a schematic diagram of a scenario of using a vehicle provided by an embodiment of the present application;

[0032] Figure 2 is a system block diagram of a torque limiting provided by an embodiment of the present application;

[0033] Figure 3 is a schematic flowchart of a method for limiting torque provided by an embodiment of the present application;

[0034] Figure 4 is a schematic diagram of correcting an initial recovery torque limit value provided by an embodiment of the present application;

[0035] Figure 5 is a structural diagram of a device for limiting torque provided by an embodiment of the present application;

[0036] Figure 6 is a structural diagram of a vehicle provided by an embodiment of the present application. Detailed Embodiments

[0037] The technical solution in the present application will be described clearly and in detail below in conjunction with the accompanying drawings. In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0038] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0039] Figure 1 It is a schematic diagram of a scenario of using a vehicle provided in an embodiment of the present application.

[0040] For example, the current remaining power of the power battery in the pure electric vehicle A is 100%, at which time the charging power allowed by the power battery is 0 kW. Figure 1 As shown in the figure, when pure electric vehicle A is driving on a 20% road slope in the driving gear, the driver lightly steps on the accelerator pedal with a pedal opening of 10%. At this time, pure electric vehicle A slips backwards and is in energy recovery mode. At this time, the drive motor in pure electric vehicle A will be converted to generator mode and generate feedback current. However, the charging power allowed by the power battery is 0kw at this time, and the power battery cannot absorb this current, which will cause the voltage of the power battery to increase, even exceeding the safety threshold, which may cause the electrolyte in the power battery to decompose and release a large amount of heat, causing fire or explosion, etc.

[0041] In order to solve the above problems, the present application embodiment proposes a method for limiting torque to avoid the problem of overcharging of the power battery in the above scenario as much as possible. The specific implementation steps can be seen as follows: Figure 3 .

[0042] This application Figure 3 One method of limiting torque relies on Figure 2 The system shown, Figure 2 As shown, the sensors in the system collect vehicle information, and the vehicle controller determines the vehicle status and battery status based on the vehicle information. When the vehicle status and battery status meet the preset status, the regenerative torque limit of the drive motor during braking is determined. When the driver requests the required braking torque, the motor controller controls the regenerative torque of the drive motor based on the regenerative torque limit.

[0043] It should be noted that this application is mainly forFigure 2 The part of determining the recovery torque limit in it is described in detail.

[0044] Figure 3 It is a schematic flowchart of a method for limiting torque provided by an embodiment of the present application.

[0045] It should be understood that a method for limiting torque provided by an embodiment of the present application can be applied to a vehicle as shown in Figure 1 (for example, pure electric vehicle A). Specifically, this method for limiting torque can be applied to the vehicle's vehicle controller.

[0046] Exemplarily, as shown in Figure 3 the method 300 includes the following steps 301 to 303.

[0047] Step 301, when the vehicle is in a driving state and the current charging power allowed by the power battery in the vehicle is less than or equal to a preset power, detect whether the current driving condition of the vehicle is an energy recovery condition, and the preset power is used to indicate that the power battery is not suitable for charging currently.

[0048] It should be understood that in the above step 301, the "vehicle" can be a pure electric vehicle. "The current charging power allowed by the power battery is less than or equal to the preset power" means that the power battery is not suitable for charging currently, which may be because the current remaining power of the power battery is very large (such as 100%) or the power battery is in a low-temperature environment. In some embodiments, the preset power is 3 kw.

[0049] Step 302, when the driving condition is an energy recovery condition, based on the required power of in-vehicle electrical equipment, the current charging power, and the target braking torque, determine the recovery torque limit of the drive motor in the vehicle during energy recovery, and the target braking torque is the braking torque limit independently provided by the vehicle's mechanical braking system under this energy recovery condition.

[0050] It should be understood that the "mechanical braking system" in the above step 302 refers to a braking system that converts kinetic energy into heat energy through physical friction. In addition, the target braking torque is the braking torque limit independently provided by the mechanical braking system under the energy recovery condition, and the mechanical braking may be activated or not activated at this time. When the mechanical braking is activated, the target braking torque is used to reflect the actual braking torque, and when the mechanical braking is not activated, the target braking torque is used to reflect the upper limit of the braking capacity of the mechanical braking system.

[0051] It should also be understood that when the driving condition of the vehicle is the energy recovery condition, the drive motor is converted into the generator mode, and there is a relationship between its recovery torque and the generated power. When the power battery is not suitable for charging at present, it is necessary to limit the recovery torque. However, the required power of in-vehicle electrical equipment directly affects the net charging / discharging capacity of the battery (current charging power - required power). If the power consumption of in-vehicle electrical equipment is too high, it will occupy the space for the regenerative power to be charged into the power battery, and even force the power battery to discharge to make up the gap. The current charging power can directly reflect the upper limit of the real-time charging capacity of the power battery. It is necessary to limit the recovery torque of the drive motor to ensure that the regenerative power does not exceed the acceptable range of the power battery, and avoid overcharging or thermal runaway. And the above-mentioned target braking torque, as the redundant capacity of mechanical braking, needs to cooperate with the braking torque of the drive motor to ensure that when the braking torque of the drive motor cannot meet the total braking torque requirement due to battery limitations, the mechanical braking can make up the remaining torque requirement, so as to dynamically balance the energy recovery efficiency and system reliability on the premise of ensuring braking safety. Therefore, the above-mentioned recovery torque limit value of the drive motor during energy recovery is determined by the required power of in-vehicle electrical equipment, the current charging power and the target braking torque.

[0052] In some embodiments, the method for determining that the driving condition in step 302 is the energy recovery condition includes: when the acceleration of the vehicle is less than the preset acceleration, determining whether the current pedal opening of the accelerator pedal in the vehicle is the preset opening or whether the braking pressure is less than the preset braking pressure; when the current pedal opening is the preset opening or the braking pressure is less than the preset braking pressure, determining whether the output torque of the drive motor is a negative torque; when the output torque is a negative torque, determining whether the power battery is in the charging state; when the power battery is in the charging state, determining that the driving condition is the energy recovery condition.

[0053] It should be understood that in the above solution, the "preset acceleration" is 0 m / s 2 , and the "preset opening" is 0%.

[0054] The following describes the "determination process of the target braking torque".

[0055] In a possible implementation manner, the method for determining the target braking torque in step 302 includes: when the mechanical braking system is not braking, determining the sum of the maximum braking torques of the brake calipers of multiple wheels in the vehicle as the target braking torque; when the mechanical braking system is braking, for any wheel in the vehicle, determining the product of the friction coefficient, braking pressure, effective piston area and effective brake disc radius of the brake caliper of the wheel as the braking torque of the brake caliper of the wheel; and determining the sum of the braking torques of the multiple wheels as the target braking torque.

[0056] It should be understood that in the above solution, "the mechanical braking system does not perform braking" means that the mechanical braking is not activated, and "the mechanical braking system performs braking" means that the mechanical braking is activated. In addition, the friction coefficient of the above brake caliper is related to the current temperature.

[0057] In the above technical solution, different from the braking state of the mechanical braking system, when the mechanical braking system is not in the braking state, the maximum braking torque of the brake calipers of each wheel is used to determine the target braking torque; when the mechanical braking system is in the braking state, the target braking torque is determined based on the dynamic product among the friction coefficient, the braking pressure, the effective piston area and the effective radius of the brake disc. This can more accurately reflect the actual available mechanical braking torque of the vehicle, thereby providing accurate input parameters for the determination of the recovery torque limit, and effectively avoiding the long-term overcharging of the power battery caused by the estimation deviation of the recovery torque. At the same time, it can also improve the cooperative control accuracy of the braking torque of the drive motor and the braking torque of the mechanical system under the energy recovery condition.

[0058] The "determination process of the recovery torque limit" is described as follows.

[0059] In a possible implementation, determining the recovery torque limit of the drive motor during energy recovery in step 302 based on the required power of the on-vehicle electrical equipment, the current charging power, and the target braking torque includes: determining the initial recovery torque limit of the drive motor during energy recovery based on the required power, the current charging power, and the target braking torque; determining a torque correction coefficient based on whether the driving direction of the vehicle is consistent with the gear state, and the torque correction coefficient is used to correct the initial recovery torque limit; multiplying the initial recovery torque limit by the torque correction coefficient to determine the recovery torque limit during the vehicle's driving.

[0060] It should be understood that the "initial recovery torque limit" in the above solution refers to the recovery torque limit initially determined through the required power, the current charging power, and the target braking torque, and its initial recovery torque limit may not be very accurate. The initial recovery torque limit can be adjusted subsequently.

[0061] It should also be understood that "whether the driving direction of the vehicle is consistent with the gear state" in the above solution refers to whether the actual driving direction of the vehicle is consistent with the direction indicated by the gear currently engaged in the gearbox. The above driving direction includes the forward direction and the reverse direction. The above gear state includes the drive gear and the reverse gear.

[0062] In the above technical solution, the initial recovery torque limit value is determined based on the required power of the in-vehicle electrical equipment, the current charging power, and the target braking torque, which can ensure that the braking torque limit value of the drive motor is always limited by the current acceptable charging power of the power battery. Subsequently, a consistency judgment of the driving direction and the gear state is introduced to generate a torque correction coefficient to dynamically adjust the initial recovery torque limit value. This dual control mechanism can not only rigidly constrain the energy recovery power through the current charging power of the power battery in the initial calculation stage, but also further suppress the recovery torque limit value through gear abnormality detection in the correction stage of the torque correction coefficient. This can achieve refined control of the recovery torque under multi-dimensional dynamic working conditions, and strictly prevent the long-term overcharging risk caused by the recovered power of the power motor exceeding the current charging capacity of the power battery.

[0063] In a possible implementation, based on the required power, the current charging power, and the target braking torque, determining the initial recovery torque limit value of the drive motor during energy recovery includes: determining the difference between the current charging power and the required power as the current available charging power of the power battery, and determining the larger power between the available charging power and a first preset power as the available recovery power; determining the ratio of the available recovery power to the current speed of the drive motor as the first torque; and determining the smaller torque between the first torque and the target braking torque as the initial recovery torque limit value.

[0064] It should be understood that in the above solution, the "first preset power" is 0 kw, and the unit of the "current speed" is rad / s.

[0065] In the above technical solution, by taking the power difference between the current charging power and the required power of the in-vehicle electrical equipment as the available charging power, it can ensure that the upper limit of the energy recovery power is always lower than the charging power acceptable to the power battery minus the net power consumed by the on-vehicle charging equipment. Further, taking the larger power between the power difference and the first preset power as the final available recovery power, that is, the first preset power as the power safety threshold, this can prevent the available power from becoming negative or too low due to a sudden increase in the required power. Subsequently, the first torque is determined based on the ratio of the available recovery power to the current speed of the drive motor, and then the smaller value is taken in combination with the target braking torque to determine the initial recovery torque limit value. The above torque limit mechanism dynamically couples the charging power of the power battery, the equipment load, the speed characteristics, and the mechanical braking torque at the calculation source, and can ensure that the recovery torque of the drive motor will not cause the input power of the power battery to exceed its current maximum allowable charging power under any working conditions by taking the boundary values with stricter constraints layer by layer, thereby reducing the long-term overcharging risk of the power battery.

[0066] In a possible implementation, a torque correction coefficient is determined based on whether the driving direction of the vehicle is consistent with the gear state, including: when the driving direction is consistent with the gear state, determining a first correction coefficient as the torque correction coefficient, where the first correction coefficient is used to indicate that the initial recovery torque limit remains unchanged; when the driving direction is not consistent with the gear state, determining a second correction coefficient based on the slip ratio of the drive wheels in the vehicle, the current vehicle speed, and the remaining power of the power battery, and determining the second correction coefficient as the torque correction coefficient, where the second correction coefficient is less than the first correction coefficient.

[0067] It should be understood that the "slip ratio of the drive wheels" in the above solution refers to the slip ratio of any drive wheel or the slip ratio of the target drive wheel, where the slip ratio of the target drive wheel is greater than that of other drive wheels.

[0068] It should also be understood that in the above solution, when the driving direction is consistent with the gear state, the torque correction coefficient is 1, that is, the initial recovery torque limit is not adjusted. When the driving direction is not consistent with the gear state, the initial recovery torque limit is adjusted downward to obtain the torque correction coefficient. In addition, the second correction coefficient is less than 1.

[0069] In the above technical solution, when the driving direction is consistent with the gear state, the first correction coefficient (usually 1) is used to keep the initial recovery torque limit unchanged, which can ensure the maximization of the energy recovery efficiency under normal working conditions. When the driving direction is not consistent with the gear state, the slip ratio of the drive wheels, the current vehicle speed, and the remaining power of the power battery are introduced to dynamically determine the second correction coefficient (usually less than 1). The slip ratio can reflect the state of the wheel grip (when the slip ratio is too high, the energy recovery intensity is reduced to avoid the drive wheels from slipping and exacerbating the energy mutation). The current vehicle speed is used to affect the time cumulative effect of the recoverable power, and the remaining power can be directly related to the power threshold of the overcharge risk of the power battery. The above multi-parameter coupled correction logic can actively reduce the recovery torque limit under abnormal working conditions (energy recovery working condition and current charging power is low), thereby avoiding the power battery from receiving power input exceeding its allowable charging power within a short time. At the same time, combining the slip ratio and the remaining power can build a double safety defense line to systematically block the long-term overcharge risk abnormally caused by mechanical and electrical coupling.

[0070] In Figure 1 In the corresponding embodiment, when the pure electric vehicle A is driving in the drive gear on a 20% road slope, the driver gently steps on the accelerator pedal with a 10% pedal opening. At this time, the pure electric vehicle A starts to roll backward. At this time, the driving direction of the pure electric vehicle A is the reverse direction, and the gear state is the drive gear. Its reverse direction is not consistent with the drive gear.

[0071] Figure 4 It is a schematic diagram for correcting the initial recovery torque limit provided by an embodiment of the present application.

[0072] Exemplarily, as Figure 4 shown, it is determined whether to correct the initial recovery torque limit based on whether the driving direction of the vehicle is consistent with the gear state. When the driving direction is not consistent with the gear state, the initial recovery torque limit is controlled to remain unchanged; when the driving direction is consistent with the gear state, a second correction coefficient is determined based on the slip ratio of the driving wheels, the current vehicle speed, and the remaining power of the power battery, and the initial recovery torque limit is corrected based on the second correction coefficient.

[0073] In some embodiments, when the gear state is the drive gear and the rotational speed of the drive motor is less than the first rotational speed, or when the gear state is the reverse gear and the rotational speed of the drive motor is greater than the second rotational speed, it is determined that the driving direction is not consistent with the gear state; when the gear state is the drive gear and the rotational speed of the drive motor is greater than the second rotational speed, or when the gear state is the reverse gear and the rotational speed of the drive motor is less than the first rotational speed, it is determined that the driving direction is consistent with the gear state.

[0074] In a possible implementation, determining the second correction coefficient based on the slip ratio of the driving wheels, the current vehicle speed, and the remaining power of the power battery in the vehicle includes: determining a third correction coefficient based on the slip ratio, the safety slip ratio threshold, and the maximum allowable slip ratio of the driving wheels; determining a fourth correction coefficient based on the current vehicle speed, the low-speed threshold, and the high-speed threshold of the vehicle; determining a fifth correction coefficient based on the remaining power, the low-power threshold, and the high-power threshold of the power battery; and determining the product of the third correction coefficient, the fourth correction coefficient, and the fifth correction coefficient as the second correction coefficient.

[0075] It should be understood that in the above solution, the maximum allowable slip ratio is greater than the safety slip ratio threshold, the high-speed threshold is greater than the low-speed threshold, and the high-power threshold is greater than the low-power threshold. In some embodiments, the safety slip ratio threshold is 10%, and the maximum allowable slip ratio is 20%. In some embodiments, the low-speed threshold is 5 km / h, and the high-speed threshold is 55 km / h. In some embodiments, the low-power threshold is 50%, and the high-power threshold is 90%.

[0076] In the above technical solution, the influence of the slip ratio of the driving wheel, the current vehicle speed of the vehicle, and the remaining power of the power battery on the torque correction coefficient is decoupled hierarchically. Based on the dynamic relationship between the slip ratio and its safety threshold and maximum allowable threshold, the third correction coefficient is determined. According to the mapping of the current vehicle speed within the range between the low-speed threshold and the high-speed threshold, the fourth correction coefficient is determined. According to the mapping of the remaining power within the range between the low-power threshold and the high-power threshold, the fifth correction coefficient is determined. Furthermore, the second correction coefficient is synthesized through the product of the three (the third correction coefficient, the fourth correction coefficient, and the fifth correction coefficient). This multi-dimensional interlocking constraint mechanism can directly weaken the recovery torque limit value when the slip ratio is abnormal to avoid the risk of sudden change of mechanical energy. The current vehicle speed can suppress the energy density of large inertia recovery when the vehicle is at high speed. The remaining power is used as a hard attenuation factor for final overcharge protection. After the three are superimposed, a strict product attenuation can be applied to the initial recovery torque limit value to ensure that the recovery torque of the drive motor is always compressed within the safety boundary of the charging power currently allowed by the power battery. This can avoid the risk of long-term overcharge of the power battery when the current charging power allowed by the power battery is low and the vehicle is in the energy recovery working condition.

[0077] The following "process of determining the third correction coefficient" is described.

[0078] In a possible implementation manner, based on the slip ratio, the safety slip ratio threshold of the driving wheel, and the maximum allowable slip ratio, determining the third correction coefficient includes: when the slip ratio is less than or equal to the safety slip ratio threshold, determining the sixth correction coefficient as the third correction coefficient; when the slip ratio is greater than the safety slip ratio threshold and less than or equal to the maximum allowable slip ratio, determining the slip ratio deviation between the slip ratio and the safety slip ratio threshold, and determining the first coefficient difference between the preset coefficient and the seventh correction coefficient as the third correction coefficient, where the seventh correction coefficient is the product of the slip ratio deviation and the first attenuation coefficient, and the first attenuation coefficient is used to indicate the attenuation amount of the torque correction coefficient corresponding to each unit percentage increase in the slip ratio; when the slip ratio is greater than the maximum allowable slip ratio, determining the eighth correction coefficient as the third correction coefficient, where the sixth correction coefficient is greater than the first coefficient difference, and the first coefficient difference is greater than the eighth correction coefficient.

[0079] It should be understood that the slip ratio is used to reflect the adhesion state between the driving wheel and the ground. When the slip ratio is high, the recovery torque limit value needs to be reduced to prevent the vehicle from getting out of control.

[0080] It should also be understood that in the above solution, when the slip ratio is less than or equal to the safe slip ratio threshold, the initial recovery torque limit is not restricted, that is, the sixth correction coefficient is 1. When the slip ratio is greater than the maximum allowable slip ratio (when over the limit), energy recovery is disabled, that is, the eighth correction coefficient is 0, the third correction coefficient is 0, the second correction coefficient is 0, the torque correction coefficient is 0, and the recovery torque limit is also 0. In addition, the above preset coefficient is 1.

[0081] It should also be noted that the "first attenuation coefficient" in the above solution specifically refers to the attenuation amount of the torque correction coefficient corresponding to each 1% increase in the slip ratio. In some embodiments, when the first attenuation coefficient is 0.1, it means that the torque correction coefficient decreases by 0.1 for each 1% exceeding the safe slip ratio threshold.

[0082] In the above technical solution, the influence of the slip ratio on the correction coefficient is processed in intervals. When the slip ratio does not exceed the safe slip ratio threshold, the initial recovery torque limit is not changed from the perspective of the slip ratio, ensuring the optimal energy recovery efficiency under low slip ratios. When the slip ratio is between the safe slip ratio threshold and the maximum allowable slip ratio, the correction coefficient is dynamically reduced based on the product of the slip ratio deviation and the first attenuation coefficient, so that the initial recovery torque limit decreases linearly with the degree of slip deterioration, suppressing the sudden input of non-steady-state electric quantity caused by the driving wheel slipping. When the slip ratio exceeds the maximum allowable slip ratio, a very low eighth correction coefficient (such as approaching zero) is directly adopted to completely block the possibility of triggering energy recovery at high slip ratios. This stepped attenuation mechanism can gradually tighten the limit on the recovery torque as the slip ratio gradually increases, preventing the instantaneous electric quantity input from exceeding the current acceptable charging power threshold of the power battery, and at the same time eliminating the long-term overcharging risk of the power battery through hard limiting when the current charging power allowed by the power battery is low and the vehicle is in the energy recovery working condition.

[0083] Optionally, based on the slip ratio, the safe slip ratio threshold and the maximum allowable slip ratio of the driving wheel, determining the third correction coefficient includes: determining the third correction coefficient based on the following formula (1);

[0084]

[0085] where k3 is the third correction coefficient, k6 is the sixth correction coefficient, λ is the slip ratio, λ safe is the safe slip ratio threshold, k0 is the preset coefficient, α1 is the first attenuation coefficient, λ max is the maximum allowable slip ratio, and k8 is the eighth correction coefficient. In addition, α1(λ - λ safe ) is the seventh correction coefficient.

[0086] The following "determination process of the fourth correction coefficient" is described.

[0087] In some embodiments, determining a fourth correction coefficient based on the current vehicle speed, the low-speed threshold, and the high-speed threshold of the vehicle includes: when the absolute value of the current vehicle speed is less than or equal to the low-speed threshold, determining the ninth correction coefficient as the fourth correction coefficient; when the current vehicle speed is greater than the low-speed threshold and less than or equal to the high-speed threshold, determining the vehicle speed deviation between the absolute value of the current vehicle speed and the low-speed threshold, and determining the second coefficient difference between the preset coefficient and the tenth correction coefficient as the fourth correction coefficient, where the tenth correction coefficient is the product of the vehicle speed deviation and the second attenuation coefficient, and the second attenuation coefficient is used to indicate the attenuation amount of the torque correction coefficient corresponding to each unit increase in vehicle speed; when the absolute value of the current vehicle speed is greater than the high-speed threshold, determining the eleventh correction coefficient as the fourth correction coefficient, where the eleventh correction coefficient is greater than the second coefficient difference, and the second coefficient difference is greater than the ninth correction coefficient.

[0088] It should be understood that the higher the vehicle speed, the more sensitive the braking effect during energy recovery when the driving direction is inconsistent with the gear state, and the intensity of energy recovery needs to be restricted.

[0089] It should also be understood that in the above solution, when the absolute value of the current vehicle speed is less than or equal to the low-speed threshold, the initial recovery torque limit is not restricted, that is, the ninth correction coefficient is 1. When the absolute value of the current vehicle speed is greater than the high-speed threshold (when over-limited), energy recovery is disabled, that is, the eleventh correction coefficient is 0, the fourth correction coefficient is 0, the second correction coefficient is 0, the torque correction coefficient is 0, and the recovery torque limit is also 0.

[0090] It should also be noted that the "second attenuation coefficient" in the above solution specifically refers to the attenuation amount of the torque correction coefficient corresponding to each 1 km / h increase in vehicle speed. In some embodiments, when the second attenuation coefficient is 0.04, it means that the torque correction coefficient decreases by 0.04 for each 1 km / h increase in vehicle speed.

[0091] Optionally, determining a fourth correction coefficient based on the current vehicle speed, the low-speed threshold, and the high-speed threshold of the vehicle includes: determining the fourth correction coefficient based on the following formula (2);

[0092]

[0093] where k4 is the fourth correction coefficient, k9 is the ninth correction coefficient, v is the current vehicle speed, v low is the low-speed threshold, k0 is the preset coefficient, β2 is the second attenuation coefficient, v high is the high-speed threshold, k 11 is the eleventh correction coefficient. In addition, β2(|v| - v low ) is the tenth correction coefficient.

[0094] The following "process for determining the fifth correction coefficient" is described.

[0095] In some embodiments, based on the remaining power, the low-power threshold and the high-power threshold of the power battery, determining the fifth correction coefficient includes: when the remaining power is less than or equal to the low-power threshold, determining the twelfth correction coefficient as the fifth correction coefficient; when the remaining power is greater than the low-power threshold and less than or equal to the high-power threshold, determining the power deviation between the remaining power and the low-power threshold, and determining the third coefficient difference between the preset coefficient and the thirteenth correction coefficient as the fifth correction coefficient, where the thirteenth correction coefficient is the product of the power deviation and the third attenuation coefficient, and the third attenuation coefficient is used to indicate the attenuation amount of the torque correction coefficient corresponding to each unit percentage increase in the remaining power; when the remaining power is greater than the high-power threshold, determining the fourteenth correction coefficient as the fifth correction coefficient, where the fourteenth correction coefficient is greater than the third coefficient difference, and the third coefficient difference is greater than the twelfth correction coefficient.

[0096] It should be understood that when the remaining power is high, the charging capacity of the power battery is limited, and it is necessary to reduce the recovery torque limit to avoid overcharging of the power battery.

[0097] It should also be understood that in the above solution, when the remaining power is less than or equal to the low-power threshold, the initial recovery torque limit is not restricted, that is, the twelfth correction coefficient is 1. When the remaining power is greater than the high-power threshold (exceeding the limit), energy recovery is disabled, that is, the fourteenth correction coefficient is 0, the fifth correction coefficient is 0, the second correction coefficient is 0, the torque correction coefficient is 0, and the recovery torque limit is also 0.

[0098] It should also be noted that the "third attenuation coefficient" in the above solution specifically refers to the attenuation amount of the torque correction coefficient corresponding to each 1% increase in the remaining power. In some embodiments, when the third attenuation coefficient is 0.1, it means that the torque correction coefficient decreases by 0.1 for each 1% increase in the remaining power.

[0099] Optionally, based on the remaining power, the low-power threshold and the high-power threshold of the power battery, determining the fifth correction coefficient includes: determining the fifth correction coefficient based on the following formula (3);

[0100]

[0101] where k5 is the fifth correction coefficient, k 12 is the twelfth correction coefficient, SOC is the remaining power, SOC low is the low-power threshold, k0 is the preset coefficient, γ3 is the third attenuation coefficient, SOC high is the high-power threshold, k 14is the fourteenth correction coefficient. In addition, γ3(SOC - SOC low ) is the thirteenth correction coefficient.

[0102] Step 303: Control the recovery torque of the drive motor during energy recovery not to exceed the recovery torque limit.

[0103] In a possible implementation, before step 303, the method 300 further includes: determining the required braking torque of the driver of the vehicle; and step 303 includes: when the required braking torque is greater than the recovery torque limit, controlling the recovery torque of the drive motor during energy recovery not to exceed the recovery torque limit, and determining the torque deviation between the required braking torque and the recovery torque limit; controlling the mechanical braking system to brake according to the torque deviation.

[0104] It should be understood that the "required braking torque of the driver" in the above solution refers to the total braking torque that the driver expects the vehicle to generate by operating the brake pedal.

[0105] In the above technical solution, through the coordinated action of dynamically distributing the drive motor braking and the mechanical braking, when the required braking torque of the driver exceeds the recovery torque limit, the recovery torque of the drive motor is preferentially and strictly limited within the safety boundary of the power battery, ensuring that the energy recovery power does not exceed the hard constraint of the charging power currently allowed by the power battery. Further, the torque deviation is determined and compensated by the mechanical braking system. This hierarchical control mechanism can not only directly block the overcharging risk of the power battery at the source, but also make up for the remaining braking torque demand in real time through the mechanical braking system, ensuring the matching of braking performance and driving intention, and avoiding insufficient vehicle braking caused by simply restricting the recovery torque of the drive motor, and then being forced to increase the energy recovery power, triggering long-term overcharging of the power battery, etc.

[0106] In some embodiments, determining the required braking torque of the driver of the vehicle includes: determining an initial required torque based on the current opening of the brake pedal depressed by the driver and the maximum braking torque allowed by the vehicle; determining a first correction factor for correcting the initial required torque based on the remaining battery charge, and determining a second correction factor for correcting the initial required torque based on the current vehicle speed and a preset vehicle speed, where the preset vehicle speed is the vehicle speed corresponding to the highest regenerative braking efficiency; determining the product of the initial required torque, the first correction factor, and the second correction factor as the required braking torque.

[0107] It should be understood that the "regenerative braking torque" in the above solution refers to the braking torque achieved by the drive motor during energy recovery.

[0108] In some embodiments, determining an initial required torque based on a current opening degree of a brake pedal depressed by a driver and a maximum braking torque allowed for the vehicle includes any one of the following: determining the initial required torque based on the following formula (4); determining the initial required torque based on the following formula (5).

[0109] T initial = T max ·(1 - e -k·α ) (4)

[0110] T initial = T max ·α n (5)

[0111] Wherein, T initial is the initial required torque, T max is the maximum braking torque, α is the current opening degree, k is a curve steepness coefficient for controlling a response relationship between a pedal opening degree and a braking torque, and n is an exponential coefficient, usually n ≥ 1, for controlling a growth rate of the braking torque. Formula (4) corresponds to an exponential function model of the braking torque, and formula (5) corresponds to a power function model of the braking torque.

[0112] In some embodiments, determining a first correction factor for correcting the initial required torque based on the remaining power includes: determining a coefficient difference between a preset coefficient and the remaining power as the first correction factor; and determining a second correction factor for correcting the initial required torque based on the current vehicle speed and a preset vehicle speed includes: determining a ratio between the current vehicle speed and the preset vehicle speed as the second correction factor.

[0113] In some embodiments, when the required braking torque is less than or equal to the regeneration torque limit, controlling the drive motor to perform energy regeneration with a torque not exceeding the regeneration torque limit.

[0114] It should be understood that in the above solution, when the required braking torque is less than or equal to the regeneration torque limit, the regeneration torque of the drive motor during energy regeneration is also limited to avoid exceeding the instantaneous charging power threshold of the power battery and extend the service life of the power battery.

[0115] It should also be understood that in some embodiments, the present application can also determine a drive torque limit of the drive motor to limit the current drive torque of the drive motor.

[0116] Figure 5 It is a schematic structural diagram of a torque limiting device provided by an embodiment of the present application.

[0117] Exemplarily, as Figure 5 shown, the device 500 includes:

[0118] A detection module 501, configured to detect whether a current driving condition of the vehicle is an energy recovery condition when the vehicle is in a driving state and a current charging power allowed by a power battery in the vehicle is less than or equal to a preset power, where the preset power is used to indicate that the power battery is not suitable for charging currently;

[0119] A determination module 502, configured to determine a recovery torque limit value of a drive motor in the vehicle during energy recovery based on a demand power of on-vehicle electrical equipment, the current charging power, and a target braking torque when the driving condition is an energy recovery condition, where the target braking torque is a braking torque limit value independently provided by a mechanical braking system of the vehicle under the energy recovery condition;

[0120] A control module 503, configured to control a recovery torque of the drive motor during energy recovery not to exceed the recovery torque limit value.

[0121] Optionally, the determination module 502 is specifically configured to: determine an initial recovery torque limit value of the drive motor during energy recovery based on the demand power, the current charging power, and the target braking torque; determine a torque correction coefficient based on whether a driving direction of the vehicle is consistent with a gear state, where the torque correction coefficient is used to correct the initial recovery torque limit value; and determine a product of the initial recovery torque limit value and the torque correction coefficient as the recovery torque limit value when the vehicle is driving.

[0122] Optionally, the determination module 502 is specifically further configured to: determine a difference between the current charging power and the demand power as a first available power, and determine a larger power of the first available power and a first preset power as an available power; determine a ratio of the available power to a current rotation speed of the drive motor as a first torque; and determine a smaller torque of the first torque and the target braking torque as the initial recovery torque limit value.

[0123] Optionally, the determination module 502 is specifically further configured to: determine a first correction coefficient as the torque correction coefficient when the driving direction is consistent with the gear state, where the first correction coefficient is used to indicate that the initial recovery torque limit value remains unchanged; and determine a second correction coefficient based on a slip ratio of drive wheels in the vehicle, a current vehicle speed, and a remaining power of the power battery and determine the second correction coefficient as the torque correction coefficient when the driving direction is not consistent with the gear state, where the second correction coefficient is less than the first correction coefficient.

[0124] Optionally, the determining module 502 is further specifically configured to: determine a third correction coefficient based on the slip ratio, the safety slip ratio threshold of the driving wheel, and the maximum allowable slip ratio; determine a fourth correction coefficient based on the current vehicle speed, the low-speed threshold and the high-speed threshold of the vehicle; determine a fifth correction coefficient based on the remaining power, the low-power threshold and the high-power threshold of the power battery; and determine the product of the third correction coefficient, the fourth correction coefficient, and the fifth correction coefficient as the second correction coefficient.

[0125] Optionally, the determining module 502 is further specifically configured to: when the slip ratio is less than or equal to the safety slip ratio threshold, determine the sixth correction coefficient as the third correction coefficient; when the slip ratio is greater than the safety slip ratio threshold and less than or equal to the maximum allowable slip ratio, determine the slip ratio deviation between the slip ratio and the safety slip ratio threshold, and determine the first coefficient difference between the preset coefficient and the seventh correction coefficient as the third correction coefficient, where the seventh correction coefficient is the product of the slip ratio deviation and the first attenuation coefficient, and the first attenuation coefficient is used to indicate the attenuation amount of the torque correction coefficient corresponding to each unit percentage increase in the slip ratio; when the slip ratio is greater than the maximum allowable slip ratio, determine the eighth correction coefficient as the third correction coefficient, where the sixth correction coefficient is greater than the first coefficient difference, and the first coefficient difference is greater than the eighth correction coefficient.

[0126] Optionally, the determining module 502 is further specifically configured to: when the mechanical braking system is not braking, determine the sum of the maximum braking torques of the brake calipers of multiple wheels in the vehicle as the target braking torque; when the mechanical braking system is braking, for any wheel in the vehicle, determine the product of the friction coefficient, the braking pressure, the effective piston area, and the effective radius of the brake disc of the brake caliper of the wheel as the braking torque of the brake caliper of the wheel; and determine the sum of the braking torques of the multiple wheels as the target braking torque.

[0127] Optionally, before controlling the recovery torque of the drive motor during energy recovery not to exceed the recovery torque limit, the determining module 502 is further configured to determine the required braking torque of the driver of the vehicle; the control module 503 is specifically configured to: when the required braking torque is greater than the recovery torque limit, control the recovery torque of the drive motor during energy recovery not to exceed the recovery torque limit, and determine the torque deviation between the required braking torque and the recovery torque limit; and control the mechanical braking system to brake according to the torque deviation.

[0128] Figure 6 It is a schematic structural diagram of a vehicle provided by an embodiment of the present application.

[0129] Exemplarily, such as Figure 6As shown, the vehicle 600 includes: a memory 601 and a processor 602. Among them, an executable program code 603 is stored in the memory 601, and the processor 602 is configured to call and execute the executable program code 603 to execute a method for limiting torque.

[0130] In addition, an embodiment of the present application also protects a device, which may include a memory and a processor. Among them, an executable program code is stored in the memory, and the processor is configured to call and execute the executable program code to execute a method for limiting torque provided by the embodiment of the present application.

[0131] This embodiment can perform a functional module division on the device according to the above method example. For example, it can correspond to each functional module, or integrate two or more functions into one processing module. The above integrated module can be implemented in the form of hardware. It should be noted that the division of modules in this embodiment is illustrative, only a logical function division, and there may be other division methods in actual implementation.

[0132] In the case of dividing each functional module corresponding to each function, the device may further include a detection module, a determination module, a control module, etc. It should be noted that all relevant contents involved in the above method embodiment can be cited in the function description of the corresponding functional module, and will not be repeated here.

[0133] It should be understood that the device provided in this embodiment is used to execute the above method for limiting torque, so it can achieve the same effect as the above implementation method.

[0134] In the case of adopting an integrated unit, the device may include a processing module and a storage module. Among them, when the device is applied to a vehicle, the processing module can be used to control and manage the actions of the vehicle. The storage module can be used to support the vehicle to execute relevant executable program codes, etc.

[0135] Among them, the processing module can be a processor or a controller, which can implement or execute various exemplary logic blocks, modules, and circuits shown in combination with the disclosure of the present application. The processor can also be a combination for implementing computing functions, such as including a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module can be a memory.

[0136] In addition, the device provided in the embodiment of the present application can specifically be a chip, a component, or a module. The chip may include a connected processor and a memory; among them, the memory is used to store instructions, and when the processor calls and executes the instructions, the chip can execute a method for limiting torque provided by the above embodiment.

[0137] This embodiment also provides a computer-readable storage medium, in which executable program code is stored. When the executable program code runs on a computer, the computer is caused to execute the above-related method steps to implement a method for limiting torque provided in the above embodiment.

[0138] This embodiment also provides a computer program product. When the computer program product runs on a computer, the computer is caused to execute the above-related steps to implement a method for limiting torque provided in the above embodiment.

[0139] Among them, the device, computer-readable storage medium, computer program product or chip provided in this embodiment are all used to execute the corresponding method provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method provided above, and will not be elaborated here.

[0140] Through the description of the above embodiments, those skilled in the art can understand that for the convenience and brevity of description, only the above division of each functional module is used as an example. In actual applications, the above functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above.

[0141] In the embodiments provided in this application, it should be understood that the disclosed device and method can be implemented in other ways. For example, the device embodiments described above are only illustrative. For example, the division of modules or units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of the device or unit can be in an electrical, mechanical or other form.

[0142] The above content is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in this application, and all should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. A method for limiting torque, characterized in that: The method comprises: When the vehicle is in a driving state and the current charging power allowed by the power battery in the vehicle is less than or equal to a preset power, detecting whether the current driving condition of the vehicle is an energy recovery condition, the preset power being used to indicate that the power battery is not currently suitable for charging; In the case where the driving condition is an energy recovery condition, determining a recovery torque limit of the drive motor in the vehicle during energy recovery based on the required power of the on-board electrical equipment, the current charging power and the target braking torque, wherein the target braking torque is a braking torque limit independently provided by the mechanical braking system of the vehicle under the energy recovery condition; The recovery torque of the driving motor during energy recovery is controlled not to exceed the recovery torque limit value.

2. The method according to claim 1, characterized in that The determining, based on the required power of the on-board electrical equipment, the current charging power and the target braking torque, of the recovery torque limit of the driving motor in the vehicle during energy recovery includes: determining an initial recovery torque limit value of the drive motor during energy recovery based on the required power, the current charging power and the target braking torque; determining a torque correction coefficient based on whether the driving direction and the gear state of the vehicle are consistent, wherein the torque correction coefficient is used to correct the initial recovery torque limit value; The product of the initial regeneration torque limit value and the torque correction coefficient is determined as the regeneration torque limit value when the vehicle is traveling.

3. The method according to claim 2, characterized in that The determining, based on the required power, the current charging power and the target braking torque, an initial recovery torque limit value of the drive motor during energy recovery includes: Determine the difference between the current charging power and the required power as the current available charging power of the power battery, and determine the larger power between the available charging power and the first preset power as the available recovery power; determining a ratio between the available regenerative power and a current rotation speed of the drive motor as a first torque; A smaller torque between the first torque and the target braking torque is determined as the initial regeneration torque limit value.

4. The method according to claim 2, characterized in that: The determining of the torque correction coefficient based on whether the driving direction of the vehicle is consistent with the gear state includes: In a case where the driving direction is consistent with the gear state, determining a first correction coefficient as the torque correction coefficient, wherein the first correction coefficient is used to indicate that the initial recovery torque limit value remains unchanged; When the driving direction is not consistent with the gear state, a second correction coefficient is determined based on the slip rate of the driving wheels in the vehicle, the current vehicle speed and the remaining power of the power battery, and the second correction coefficient is determined as the torque correction coefficient, and the second correction coefficient is smaller than the first correction coefficient.

5. The method according to claim 4, characterized in that The determining of the second correction coefficient based on the slip rate of the driving wheel in the vehicle, the current vehicle speed and the remaining power of the power battery includes: determining a third correction coefficient based on the slip ratio, a safety slip ratio threshold value of the driving wheel, and a maximum allowable slip ratio; determining a fourth correction coefficient based on the current vehicle speed, a low speed threshold and a high speed threshold of the vehicle; Determining a fifth correction coefficient based on the remaining power, a low power threshold and a high power threshold of the power battery; The product of the third correction coefficient, the fourth correction coefficient and the fifth correction coefficient is determined as the second correction coefficient.

6. The method according to claim 5, characterized in that The determining of a third correction coefficient based on the slip rate, the safety slip rate threshold of the driving wheel and the maximum allowable slip rate comprises: When the slip ratio is less than or equal to the safety slip ratio threshold, determining a sixth correction coefficient as the third correction coefficient; In the case where the slip ratio is greater than the safety slip ratio threshold and less than or equal to the maximum allowable slip ratio, determining a slip ratio deviation between the slip ratio and the safety slip ratio threshold, determining a first coefficient difference between a preset coefficient and a seventh correction coefficient as the third correction coefficient, the seventh correction coefficient being the product of the slip ratio deviation and a first attenuation coefficient, the first attenuation coefficient being used to indicate an attenuation amount corresponding to a torque correction coefficient when the slip ratio increases by a unit percentage value; When the slip ratio is greater than the maximum allowable slip ratio, the eighth correction coefficient is determined as the third correction coefficient, the sixth correction coefficient is greater than the first coefficient difference, and the first coefficient difference is greater than the eighth correction coefficient.

7. The method according to claim 1, characterized in that The method for determining the target braking torque includes: When the mechanical brake system is not braking, determining the sum of the maximum braking torques of the brake calipers of the plurality of wheels in the vehicle as the target braking torque; When the mechanical brake system is braking, for any wheel in the vehicle, the product of the friction coefficient of the brake caliper of the wheel, the braking pressure, the effective area of ​​the piston and the effective radius of the brake disc is determined as the braking torque of the brake caliper of the wheel; and the sum of the braking torques of the multiple wheels is determined as the target braking torque.

8. The method according to claim 1, characterized in that Before the recovery torque of the driving motor is controlled to not exceed the recovery torque limit value during energy recovery, the method further includes: determining a demanded brake torque of a driver of the vehicle; And, controlling the recovery torque of the drive motor during energy recovery not to exceed the recovery torque limit value comprises: When the required braking torque is greater than the recovery torque limit, controlling the recovery torque of the drive motor during energy recovery not to exceed the recovery torque limit, and determining a torque deviation between the required braking torque and the recovery torque limit; The mechanical brake system is controlled to perform braking according to the torque deviation.

9. A torque limiting device, characterized in that: The device comprises: a detection module, used to detect whether the current driving condition of the vehicle is an energy recovery condition when the vehicle is in a driving state and the current charging power allowed by the power battery in the vehicle is less than or equal to a preset power, wherein the preset power is used to indicate that the power battery is not suitable for charging at present; a determination module, configured to determine, when the driving condition is an energy recovery condition, a recovery torque limit of the drive motor in the vehicle during energy recovery based on the required power of the on-board electrical equipment, the current charging power and the target braking torque, wherein the target braking torque is a braking torque limit independently provided by the mechanical braking system of the vehicle under the energy recovery condition; The control module is used to control the recovery torque of the drive motor during energy recovery so as not to exceed the recovery torque limit value.

10. A vehicle, characterized in that: The vehicle comprises: A memory for storing executable program codes; A processor, configured to call and run the executable program code from the memory, so that the vehicle executes the method according to any one of claims 1 to 8.

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